This design, a reproduction of a modern-type transport plane in flight, was
used on a set of seven stamps in a uniform series to replace similar
denominations in use, which had been issued at various intervals since 1926.

This series was issued during a period of time when the Douglas DC-3 twin
-engine planes of pre-World War II were being used widely and successfully, and
the new four-engine planes were being brought into service quickly because of
war needs.

The DC-3 featured such advances as all-metal stressed-skin construction, a
radial engine, internally braced wings, retractable landing gear, and the
controllable-pitch propeller.